diff options
Diffstat (limited to 'drivers/clk/clk.c')
| -rw-r--r-- | drivers/clk/clk.c | 40 |
1 files changed, 40 insertions, 0 deletions
diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c index dee9c528ea83..5a1507498e05 100644 --- a/drivers/clk/clk.c +++ b/drivers/clk/clk.c @@ -2253,6 +2253,38 @@ static inline void clk_debug_unregister(struct clk_core *core) #endif /** + * __clk_is_ancestor - check if a clk_core is a possible ancestor of another + * @core: clock core + * @ancestor: ancestor clock core + * + * Returns true if there is a possibility that @ancestor can be an ancestor + * of @core, false otherwise. + * + * This function can be used against @core or @ancestor that has not been + * registered yet. + */ +static bool __clk_is_ancestor(struct clk_core *core, struct clk_core *ancestor) +{ + struct clk_core *parent; + int i; + + for (i = 0; i < core->num_parents; i++) { + parent = clk_core_get_parent_by_index(core, i); + /* + * If ancestor has not been added to clk_{root,orphan}_list + * yet, clk_core_lookup() cannot find it. If parent is NULL, + * compare the name strings, too. + */ + if ((parent && (parent == ancestor || + __clk_is_ancestor(parent, ancestor))) || + (!parent && !strcmp(core->parent_names[i], ancestor->name))) + return true; + } + + return false; +} + +/** * __clk_core_init - initialize the data structures in a struct clk_core * @core: clk_core being initialized * @@ -2317,6 +2349,14 @@ static int __clk_core_init(struct clk_core *core) "%s: invalid NULL in %s's .parent_names\n", __func__, core->name); + /* If core is an ancestor of itself, it would make a loop. */ + if (__clk_is_ancestor(core, core)) { + pr_err("%s: %s would create circular parent\n", __func__, + core->name); + ret = -EINVAL; + goto out; + } + core->parent = __clk_init_parent(core); /* |